<span>As the pollen tube penetrates the ovule, it releases two sperm cells. As in gymnosperms, the ovule becomes a seed, encasing the embryo and endosperm in a seed coat. But unlike gymnosperms, in angiosperms the ovary containing the ovules develops into a fruit after fertilization.</span>
Some factors could be:
weather
ressources
That is called Urogenital myiasis which is a parasitic infestation. These flies are in the Diptera species group and the cause of this myiasis is from the eggs and larvae of this species (fly).
Let me know if you need further info.
- Dotz
I think the answer is c but I looked it up and got this: system or thing used as an example to follow or imitate.
In frogs, different mating seasons are a barrier to reproduction.